I won't even listen to a record in the shop for fear that the crappy cartridges and TTs will damage the vinyl. At one shop, the tonearm on the their TT did not have an offset angle, straight arm with a straight head shell. I felt like explaining the importance of the offset angle, but I figured they really wouldn't care anyways.
To ensure the record is okay, I remove it from the sleeve and visually inspect it. If there are any signs of possible blemishes it goes back in the bin. Also I make sure, I can exchange the record if there is any problems.
When it comes to rare recordings, I am amazed at the prices they charge for records that are in a questionable state at best or are essentially un playable. I guess there is a sucker born every minute!